Endocrine Pharmacology Practice Questions

Q: Which of the following corticosteroids has the least mineralocorticoid activity?

Triamcinolone. **Explanation:** The potency of corticosteroids is determined by their relative **glucocorticoid** (anti-inflammatory) and **mineralocorticoid** (salt-retaining) activities. **Why Triamcinolone is the correct answer:** Glucocorticoids are classified based on their duration of action and side-effect profile. **Triamcinolone**, along with **Dexamethasone** and **Betamethasone**, is a synthetic steroid designed to maximize anti-inflammatory effects while minimizing mineralocorticoid activity. However, among the options provided, Triamcinolone is traditionally classified as having **zero (negligible)** mineralocorticoid activity. While Dexamethasone and Betamethasone also have minimal salt-retaining effects, Triamcinolone is the classic textbook answer for the "least" or "nil" mineralocorticoid activity in this comparative group. **Analysis of Incorrect Options:** * **Fludrocortisone (A):** This is a potent mineralocorticoid. It has the highest salt-retaining activity among the options and is used clinically for replacement therapy in Addison’s disease. * **Dexamethasone (B) & Betamethasone (D):** These are long-acting, highly potent glucocorticoids. While they have negligible mineralocorticoid activity, they are often ranked slightly behind Triamcinolone in terms of pure "zero" salt retention in comparative pharmacology tables. **High-Yield NEET-PG Pearls:** * **Highest Mineralocorticoid Potency:** Fludrocortisone > Aldosterone > Desoxycorticosterone acetate (DOCA). * **Highest Glucocorticoid Potency:** Betamethasone > Dexamethasone > Triamcinolone > Prednisolone > Hydrocortisone. * **Drug of Choice for Cerebral Edema:** Dexamethasone (due to high potency and low salt retention). * **Fetal Lung Maturity:** Betamethasone or Dexamethasone are used because they cross the placenta and have low protein binding. * **Triamcinolone side effect:** It is specifically associated with muscle wasting (myopathy) more than other steroids.

Q: Mestranol acts as a contraceptive by:

Inhibiting FSH secretion. **Explanation:** **Mestranol** is a synthetic estrogen and a prodrug of ethinyl estradiol, commonly used in combined oral contraceptive pills (COCPs). **1. Why Option A is Correct:** The primary mechanism of the **estrogen component** (like Mestranol) in COCPs is the **suppression of Follicle Stimulating Hormone (FSH)** via negative feedback on the anterior pituitary. By inhibiting FSH, the recruitment and maturation of ovarian follicles are prevented, ensuring there is no dominant follicle to release an egg. **2. Why Other Options are Incorrect:** * **Option B (Inhibiting LH secretion):** This is the primary mechanism of the **Progestogen component**. Progesterone suppresses Luteinizing Hormone (LH) surge, thereby preventing ovulation. While estrogen contributes to this, its hallmark action is FSH suppression. * **Option C (Inhibiting tubal motility):** This is a secondary effect of **Progesterone**, which alters the contractility of the fallopian tubes to slow down ovum/zygote transport. * **Option D (Inhibiting nidation):** This refers to making the endometrium unfavorable for implantation, another secondary effect primarily mediated by **Progesterone** (causing early secretory changes and subsequent atrophy). **Clinical Pearls for NEET-PG:** * **Mestranol vs. Ethinyl Estradiol:** Mestranol is less potent because it must be converted to ethinyl estradiol in the liver. * **The "Double Lock" Mechanism:** COCPs are highly effective because they inhibit ovulation through two pathways: Estrogen (FSH suppression) + Progesterone (LH surge suppression). * **Hostile Cervical Mucus:** The most important contraceptive effect of progestogen-only pills (Mini-pills) is thickening the cervical mucus to prevent sperm penetration.

Q: Saheli or Centchroman contains which of the following active pharmaceutical ingredients?

Ormeloxifene. **Explanation:** **Correct Option: C. Ormeloxifene** Saheli (Centchroman) is a unique, non-steroidal oral contraceptive pill developed by the Central Drug Research Institute (CDRI), Lucknow. Its active ingredient is **Ormeloxifene**, which belongs to the class of **Selective Estrogen Receptor Modulators (SERMs)**. The mechanism of action is based on its competitive antagonism of estrogen receptors in the uterus. By blocking these receptors, it prevents the normal proliferative changes in the endometrium, making it asynchronous and unsuitable for implantation. It also alters cervical mucus and increases tubal motility. Because it is non-steroidal, it does not suppress ovulation, meaning the hypothalamic-pituitary-ovarian axis remains intact. **Incorrect Options:** * **A & D (Estrogen + Progesterone / Steroids):** Traditional Combined Oral Contraceptive Pills (COCPs) contain steroids (Ethinylestradiol and Progestogens). Saheli is specifically marketed as a **non-steroidal** alternative, avoiding side effects like weight gain, nausea, and increased risk of thromboembolism. * **B (Raloxifene):** While Raloxifene is also a SERM, it is primarily used for the prevention and treatment of osteoporosis in postmenopausal women and to reduce the risk of invasive breast cancer, not as a contraceptive. **High-Yield Clinical Pearls for NEET-PG:** * **Dosage Schedule:** It is taken **twice weekly** for the first 3 months (e.g., Sunday and Wednesday), followed by **once weekly** thereafter. * **Failure Rate:** The Pearl Index is approximately **1.83 to 1.96**. * **Side Effects:** The most common side effect is **delayed menstrual cycles** (prolonged cycles), which occurs in about 8% of users. * **Contraindications:** Polycystic Ovarian Syndrome (PCOS), cervical dysplasia, and recent history of jaundice or liver disease. * **Government Program:** It is included in the National Family Planning Program of India under the brand name **'Chhaya'**.

Q: Which of the following is a serious adverse effect seen with zoledronate?

Acute renal failure. **Explanation:** **Zoledronate (Zoledronic acid)** is a high-potency, intravenous nitrogen-containing bisphosphonate used primarily for osteoporosis, Paget’s disease, and bone metastases. **Why Acute Renal Failure is the correct answer:** Zoledronate is excreted unchanged by the kidneys. When administered intravenously, especially if infused too rapidly (less than 15 minutes) or in dehydrated patients, it can cause **acute tubular necrosis (ATN)**. It leads to a transient increase in serum creatinine and, in severe cases, acute renal failure. Therefore, monitoring creatinine clearance and ensuring adequate hydration before administration is mandatory. **Analysis of Incorrect Options:** * **B. Ventricular fibrillation:** While bisphosphonates (especially zoledronate) have been associated with an increased risk of **Atrial Fibrillation** in some trials, they are not typically associated with ventricular fibrillation. * **C. Peptic ulcer:** This is a classic side effect of **oral bisphosphonates** (like Alendronate) due to direct esophageal and gastric mucosal irritation. Since Zoledronate is given IV, it bypasses the GI tract and does not cause peptic ulcers. * **D. Anterior uveitis:** While bisphosphonates can cause ocular inflammation (like scleritis or uveitis), it is considered a rare idiosyncratic reaction rather than a common "serious" adverse effect compared to the systemic impact of renal failure. **High-Yield Clinical Pearls for NEET-PG:** * **Osteonecrosis of the Jaw (ONJ):** A high-yield adverse effect associated with long-term, high-dose IV bisphosphonate therapy, often triggered by invasive dental procedures. * **Acute Phase Reaction:** Patients often experience flu-like symptoms (fever, myalgia) within 24–72 hours of the first IV infusion. * **Contraindication:** Zoledronate is generally contraindicated if Creatinine Clearance (CrCl) is **<35 mL/min**.

Q: Which of the following drugs has visual field defects as an adverse effect?

Pegvisomant. **Explanation:** **Correct Option: C. Pegvisomant** Pegvisomant is a **Growth Hormone (GH) receptor antagonist** used in the treatment of acromegaly. It works by blocking the peripheral action of GH, thereby reducing the production of Insulin-like Growth Factor-1 (IGF-1). The mechanism behind **visual field defects** with Pegvisomant is unique: because it effectively lowers IGF-1 levels, it removes the negative feedback inhibition on the pituitary gland. This can lead to a compensatory **increase in GH secretion** and, more importantly, potential **growth of the underlying pituitary adenoma**. As the tumor expands (adenoma progression), it can compress the **optic chiasm**, resulting in bitemporal hemianopia or other visual field defects. Regular MRI monitoring of the pituitary is mandatory during therapy. **Incorrect Options:** * **A & B (Cabergoline & Bromocriptine):** These are Dopamine (D2) agonists used to treat prolactinomas and acromegaly. They typically cause **tumor shrinkage**, which helps *improve* visual field defects rather than causing them. * **D (Leuprolide):** This is a GnRH analog used for prostate cancer and precocious puberty. Its side effects are primarily related to hypoestrogenism/hypoandrogenism (e.g., hot flashes, bone loss), not visual field changes. **High-Yield Clinical Pearls for NEET-PG:** * **Pegvisomant:** Most potent drug for normalizing IGF-1 levels in acromegaly. * **Monitoring:** Liver Function Tests (LFTs) must be monitored as it can cause asymptomatic elevation of liver enzymes. * **Acromegaly Treatment Hierarchy:** Surgery is the first line; Somatostatin analogs (Octreotide) are the first-line medical therapy; Pegvisomant is used for resistant cases.

Q: A young female presents with a history of intercourse 5 hours prior. Select the drug that can act as a single-dose postcoital contraceptive.

Mifepristone. **Explanation:** **Mifepristone (Option B)** is a potent competitive antagonist at progesterone receptors. In the context of emergency contraception, it acts by delaying or inhibiting ovulation (if taken pre-ovulatory) and altering the endometrium to prevent implantation (if taken post-ovulatory). A single dose of **10–25 mg** is highly effective as a postcoital contraceptive and is often preferred due to fewer side effects (like nausea/vomiting) compared to the Yuzpe regimen. **Analysis of Incorrect Options:** * **Clomiphene citrate (A):** A Selective Estrogen Receptor Modulator (SERM) used primarily for **ovulation induction** in infertility; it would be counterproductive in this scenario. * **Danazol (C):** An androgen derivative used in endometriosis and hereditary angioedema. While it was historically used for emergency contraception, it requires multiple doses and is far less effective and more toxic than modern options. * **Medroxyprogesterone acetate (D):** A progestin used for long-term contraception (DMPA injections) or menstrual cycle regulation. It is not used as a single-dose emergency contraceptive. **High-Yield NEET-PG Pearls:** * **Levonorgestrel (LNG):** The most common single-dose emergency contraceptive (1.5 mg) used within 72 hours. * **Ulipristal Acetate:** A Selective Progesterone Receptor Modulator (SPRM) effective up to **120 hours (5 days)** post-intercourse. * **Copper T (IUCD):** The **most effective** emergency contraceptive method if inserted within 5 days. * **Mifepristone Dosing:** 10–25 mg for emergency contraception; 200 mg (combined with Misoprostol) for medical abortion.

Q: Mifepristone used for medical abortion is:

Anti-progesterone. **Explanation:** **Mifepristone (RU-486)** is a synthetic steroid that acts as a potent **competitive receptor antagonist** at the progesterone receptor level. Progesterone is essential for the maintenance of pregnancy as it stabilizes the endometrial lining, inhibits uterine contractions, and maintains the cervical plug. By blocking these receptors, Mifepristone leads to decidual necrosis, detachment of the products of conception, and sensitization of the myometrium to prostaglandins. **Analysis of Options:** * **B. Anti-progesterone (Correct):** Mifepristone binds to progesterone receptors with higher affinity than endogenous progesterone, effectively terminating the hormonal support required for pregnancy. * **A. Anti-estrogen:** Drugs like Clomiphene or Tamoxifen are anti-estrogens. Mifepristone has weak anti-estrogenic activity but its primary clinical function is anti-progestational. * **C. Anti-folate:** Methotrexate is an anti-folate (dihydrofolate reductase inhibitor) used in the medical management of ectopic pregnancy, not the standard regimen for intrauterine medical abortion. * **D. Prostaglandin derivative:** Misoprostol (PGE1) is the prostaglandin derivative used in combination with Mifepristone to cause uterine contractions and expulsion of the fetus. **High-Yield Clinical Pearls for NEET-PG:** 1. **Dosage for Medical Abortion:** 200 mg Mifepristone orally, followed 36–48 hours later by 800 mcg Misoprostol (vaginal/oral/sublingual). 2. **Legal Limit:** In India (MTP Act), medical abortion is approved up to **9 weeks (63 days)** of gestation. 3. **Other Uses:** Mifepristone is also used in **Cushing’s Syndrome** (anti-glucocorticoid effect at high doses), emergency contraception, and management of uterine fibroids. 4. **Side Effects:** Heavy bleeding and abdominal cramps are the most common side effects during the procedure.

Q: Milk production is inhibited by which of the following medications?

Bromocriptine. **Explanation:** The correct answer is **A. Bromocriptine**. **Mechanism of Action:** Milk production (lactogenesis) is primarily controlled by **Prolactin**, a hormone secreted by the anterior pituitary. Prolactin secretion is under tonic inhibition by **Dopamine** (also known as Prolactin-Inhibiting Hormone). **Bromocriptine** is a potent **Dopamine (D2) receptor agonist**. By mimicking dopamine, it suppresses the secretion of prolactin from the pituitary gland, thereby effectively inhibiting milk production and secretion. It is clinically used to treat hyperprolactinemia and to suppress lactation when medically indicated. **Analysis of Incorrect Options:** * **B. Ergotamine:** While an ergot alkaloid like bromocriptine, it acts primarily as a vasoconstrictor (used in migraines) and does not have the specific dopaminergic potency required to suppress prolactin significantly. * **C. Metoclopramide:** This is a **Dopamine antagonist**. By blocking dopamine receptors, it removes the natural inhibition on prolactin, leading to *increased* milk production (galactagogue effect). * **D. Estrogen:** While high levels of estrogen during pregnancy inhibit the *action* of prolactin on the breast tissue, estrogen itself does not inhibit the *production* of prolactin. In fact, estrogen can stimulate prolactin-secreting cells. **High-Yield NEET-PG Pearls:** * **Dopamine = Prolactin Inhibiting Factor (PIF).** Any drug that increases dopamine (e.g., Cabergoline, Bromocriptine) decreases prolactin. * **Cabergoline** is currently the preferred drug over Bromocriptine for lactation suppression due to its longer half-life and better side-effect profile. * **TRH (Thyrotropin-Releasing Hormone)** acts as a prolactin-releasing factor; thus, primary hypothyroidism can lead to hyperprolactinemia. * **Suckling reflex** inhibits dopamine release, thereby increasing prolactin and promoting milk production.

Question 1

A 52-year-old postmenopausal patient has evidence of low bone mineral density. She and her physician are considering therapy with raloxifene or a combination of conjugated estrogens and medroxyprogesterone acetate. Which of the following patient characteristics is MOST likely to lead them to select raloxifene?

Accepted Answer

Strong family history of breast cancer

Answer

Previous hysterectomy

Answer

Recurrent vaginitis

Answer

Troublesome hot flushes

Question 2

Which of the following corticosteroids has the least mineralocorticoid activity?

Accepted Answer

Triamcinolone

Answer

Fludrocortisone

Answer

Dexamethasone

Answer

Betamethasone

Question 3

Mestranol acts as a contraceptive by:

Accepted Answer

Inhibiting FSH secretion

Answer

Inhibiting LH secretion

Answer

Inhibiting tubal motility

Answer

Inhibiting nidation

Question 4

Which corticosteroid has the maximum sodium-retaining potential?

Accepted Answer

Fludrocortisone

Answer

Hydrocortisone

Answer

Prednisolone

Answer

Deoxycorticosterone

Question 5

Saheli or Centchroman contains which of the following active pharmaceutical ingredients?

Accepted Answer

Ormeloxifene

Answer

Estrogen + progesterone

Answer

Raloxifene

Answer

Steroid

Question 6

Which of the following is a serious adverse effect seen with zoledronate?

Accepted Answer

Acute renal failure

Answer

Ventricular fibrillation

Answer

Peptic ulcer

Answer

Anterior uveitis

Question 7

Which of the following drugs has visual field defects as an adverse effect?

Accepted Answer

Pegvisomant

Answer

Cabergoline

Answer

Bromocriptine

Answer

Leuprolide

Question 8

A young female presents with a history of intercourse 5 hours prior. Select the drug that can act as a single-dose postcoital contraceptive.

Accepted Answer

Mifepristone

Answer

Clomiphene citrate

Answer

Danazol

Answer

Medroxyprogesterone acetate

Question 9

Mifepristone used for medical abortion is:

Accepted Answer

Anti-progesterone

Answer

Anti-estrogen

Answer

Anti-folate

Answer

Prostaglandin derivative

Question 10

Milk production is inhibited by which of the following medications?

Accepted Answer

Bromocriptine

Answer

Ergotamine

Answer

Metoclopromide

Answer

Estrogen

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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